The SP-11N is a VoIP phone paging module supported SIP (Session Initiation Protocol) with Auto-answer  function. It can be connected to an IP network and directly registered as one SIP phone station on various SIP server management software. It also has VOX and mute functions designed for use with TOA’s 9000M2, 900, 700 and BG-2000 series amplifiers.

 *Now Compatibility with Cisco Unified Call Manager (CUCM)

Details: How to use a TOA SIP Client with Cisco Unified Call manager

Solution: Please see this document

The SP-11N  does not support "compact headers" sometimes also called "long headers".

Solution is to use the Cisco SIP normalization script in CUCM 11.5 to remove proprietary and nonstandard SIP Headers and Identification Services and make sip header as per rfc3261

Cisco Reference

https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2015/pdf/BRKCOL-2455.pdf

   (browser manual)  TOA SIP Client with CUCM

* Asterisk White Paper